It is proposed to design, package, and evaluate active electrodes that are reliable and easily applied without conductive paste and abrasive skin preparation. They will be used for EEG monitoring, especially for steady state evoked potential (SSEP) measurements in pediatric patients to estimate their sensory thresholds. A electronic device is to be incorporated at the electrode site. This eliminates the need for conductive pastes and skin abrasion while providing a low impedance output to minimize the electrical artifact and external interference. Based on the research results of the principal investigator from 1969 to 1975, and today's advanced integrated circuit technology, the electronic device and an interface circuit used to couple the electrode to the EEG instrument, will be miniaturized. The electronic device will be packaged with the electrode. The interface circuit will be packaged into a small box, including battery. The active electrode is connected to the interface unit; the interface is connected to the instrument with two wires in the same way as the conventional electrode. PROPOSED COMMERCIAL APPLICATION: The active electrode when mass produced may cost the same as the conventional electrode but with greater ease of operation, less irritation to the skin, and less time needed to prepare the skin. Therefore, it may be used to replace the disposable electrode now used in EEG, EOG, EMG, and EKG pick-up in the routine medical care of patients, especially for babies with tender skin.